The role of magnetic flux in preventing scale on pipes has long been known, as evidenced by U.S. Pat. No. 438,579 dated Oct. 14, 1890, A.. Faunce, et al. Electromagnets for such purposes are represented by U.S. Pat. Nos. 531,183, Dec. 18, 1894, J. Harris; 2,652,925, Sept. 22, 1953, T. Vermeiren and 4,151,090, April 24, 1979, M. Brigante. Such systems are difficult to install and maintain, requiring electrical current connections and creating magnetic disturbances to sensitive electronic equipment in the vicinity.
Thus, permanent magnet configurations have been introduced such as set forth in U.S. Pat. Nos. 3,228,878, Jan. 11, 1966, D. Moody; and 4,367,143, Jan. 4, 1983, R. Carpenter. In these devices, longitudinally oriented magnets have a flux passing between north and south poles in narrow slice like flux paths that encompass only small portions of the cross section area inside the pipe, so that only portions of the passing fluid are subjected to the magnetic flux.
U.S. Pat. No. 4,605,498, Aug. 12, 1986, P. Kulish provides a magnet array encircling the pipe circumference and magnetized to present opposite poles radially from the outer pipe circumference to outer magnet circumference. This construction is quite ineffective and introduces significant problem in adaption to pipes already installed or those with limited accessibility. For example, a different model of magnet must be custom built for close fit with every different pipe size. With large pipe sizes of six inches (15 cm) or more in diameter such magnets are impractical, very large and very expensive. Furthermore heavy flux concentrations necessary for proper fluid treatment are not feasible with this construction. The major flux path between north and south poles is thus directed in air outside the pipe and is ineffective in establishing a concentrated working flux within the fluid.
Accordingly it is an objective of this invention to improve the art of permanent magnetic flux scale and corrosion control devices, and resolve these prior art problems.